Image:The media had been told Theresa May would make a signal which would placate the EU

Money isn't the only issue about which the PM must satisfy her EU partners by the crucial December European Council deadline.

There are two more: one on citizens' rights (for those British who live in the EU and vice versa) and the other on the thorny issue of the Irish border. The Irish government has made it clear that no Brexit outcome which in any way introduces any element of a hard border on the island of Ireland is acceptable to them.

The Irish Prime Minister Leo Varadkar, talking to me at the close of the summit, has thrown a spanner in the Brexit works by saying that far from being close to a deal on the Irish border, the UK "isn't even close".

Image:Theresa May talks to her Irish counterpart Leo Varadkar (L)

"I can't say in any honesty that it's close, either on the Irish issue of the financial settlement," he said.

Mr Varadkar went on: "Brexit is a British policy, it's also one that Britain has imposed on the rest of Europe.

"It's causing enormous difficulties for the whole of Europe and Ireland in particular and to me it seems that after 40 years of marriage, most of them good, Britain wants a divorce and wants an open relationship that day after."

This will be greeted with dismay in Downing Street.

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The Irish Prime Minister went on to say that so dissatisfied was he with the British government's ideas on the Irish question to date that he wanted nothing short of a full legal guarantee from the British government to ensure that no hard border would take effect.

The problem with that is that the only way to really ensure there is no hard border at all would be for the UK to remain in the customs union and probably the single market too.

That would solve the Irish question for Theresa May but it would throw up a thousand others, mainly from her own backbenchers, for whom the price of continued customs union and single market membership would be far too high.

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For the Prime Minister it must feel she's playing Brexit whack a mole. Every time she beats one problem, a few more appear.

But she can't ignore the Irish problem. Because just like the other 26 EU countries, they have the power of veto; over both the final EU deal and whether or not Britain can pass onto the next stage of negotiations.

And so it comes to pass that Brexit, where we were meant to take back control, has thrown up a unique historical conundrum.

For the first time in the seven or eight century relationship between Britain and Ireland, the Irish exercise power over its larger neighbour.

As the Irish PM told me: "We're negotiating with the strength of 27 states, 26 member states behind us, 400 million people. We're in a very strong position here."

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They're determined to use that power and make Mrs May's life that bit harder.

And for my money the Irish problem is much worse than the financial one.

Ultimately if the difference is 10 billion or 20 or 50, the UK will find the money if it makes the difference. Britain is a £1.7trn economy, a few billion here or there is a rounding error.

The issues around culture, history and sectarianism between Irish north and south are far more intractable. You can't write a cheque and make them go away. And Brexit brings them back into the open.